HIGH SPEED INFRARED SOLID STATE THERMAL TEST SYSTEM
Original Publication Date: 1999-Jun-01
Included in the Prior Art Database: 2002-Aug-12
Solid State devices need to be characterized for thermal performance to ensure long-term device reliability. Concurrent observation of leakage cur- rents (IGSYIDSS) or voltage drops (VDS) with temperature in a dynamic mode greatly increases our understanding of the device in real applications. By applying a known or varying pulse (Figure 1) of device voltage/current and triggering simultaneously an infrared thermal imaging camera for the duration of this pulse we are capable of illustrating as a func- tion of time both the temperature and leakage cur- rents/voltage drops across the whole Solid State device surface at a millisecond frame rate interval (Figures 2 and 3). Dynamic performance character- istics and locations of defect sites can be observed visually and compared with various design configu- rations. The prior test system had very limited capa- bility of linking the voltage/current with the thermal dynamics of the solid state device. It is designed only to measure current/voltage for IGSWIDSS or VDS with temperature via a temperature sense diode on the solid state device. The temperature sense diode provides only a single point measure- ment. This eliminates the understanding of thermal gradients, heat sources, or identification of point defects. Once the device goes into thermal overload, the temperature sense diode is disabled. Prior ther- mal imaging techniques did not have triggering capabilities, preventing the synchronization of stim ulus pulses with temperature. The information obtained can be used to optimize the design parame- ters and/or better understand failure mechanisms.